Have you ever stained a wood piece, only to find the wood stain was significantly darker than you expected it to be? Well, there’s a way around that.
Wood stain can be diluted with minerals spirits, water, or lacquer thinner, depending on the type of stain. Mineral spirits dilute oil-based wood stains and gel stains, water dilutes water-based stains, and lacquer thinner dilutes lacquer-based stains.
Diluting wood stain is easy, and there are plenty of great reasons it’s worth you’re time, so lets dive in!
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Why to Dilute Wood Stain
There have been many times where I’ve started a project with an exact outcome in mind, and then was disappointed in the end because the stain I put on the piece wasn’t exactly what I was envisioning.
Thinning wood stain is a great technique for getting better control over the color of your wood. By thinning the stain, you can apply multiple lighter coats to slowly darken the piece, and end up with the exact color you were envisioning.
Note that this gets harder to do when staining really large items, like a backyard deck, for two reasons. First off, consistently thinning large amounts of stain to the exact same shade can be tricky.
Secondly, large items take longer to stain, and it might take more time than it’s worth to apply multiple coats of thinned stain to the project.
Have you ever noticed that all of Varathane’s 1 quart wood stains cost the same price, no matter what the color is?
Yet, Dark Walnut can be thinned to look more like Special Walnut… and if you thin a quart of Dark Walnut, you’ll end up with a lot more Special Walnut than if you purchased the quart.
Admittedly, a thinned Dark Walnut doesn’t look exactly like Special Walnut. But it can get pretty close.
You’re not going to get rich off this technique, but it’s a good way to save a few bucks here and there. And it’s a great option if you just want a “medium wood” color on a small project, and all you have around is dark stain.
I’ve definitely avoided purchasing a new can of stain a few times by simply diluting the stain I already have.
Spraying the Stain
Wood stain is already a pretty thin product, but sometimes sprayers require even thinner stain in order to spray it.
Diluting the wood stain is one way to prepare the stain to be sprayed on the piece.
Note, though, that this will change the color of the stain, as mentioned above. So if you’re diluting the stain purely to spray it, be sure you take that into consideration when you’re picking out the color.
How to Thin Stain
There are multiple types of wood stain out there, and each is thinned a little bit differently, so I’m going to break this down by type of stain.
Traditional Oil-Based Wood Stain
Traditional oil-based wood stain is thinned with mineral spirits. The amount of thinner you’re going to want to add is dependent on how much you want to thin the stain. Here’s the general process I use:
Step 1: Add Stain
Stir the stain to mix in any pigments that sunk to the bottom of the can, then pour an appropriate amount of stain into a spare container. If you’re only mixing a small amount of stain, old tupperware containers work great for this.
Note how much stain you poured, that way, if you need to recreate the mix later, you know exactly how much of each liquid to add.
Step 2: Add Mineral Spirits
Then add a measured amount of mineral spirits. The key here is to know how much you’re adding. I typically start with a small amount (like a tablespoon if I started with a cup of stain,) and work upward, recording what I’ve added as I go so I can recreate the mixture later if I need to.
Mix the stain and mineral spirits thoroughly before the next step.
Step 3: Test Stain
Grab some scrap wood, and test the thinned stain. Is it light enough yet? If so, awesome. If not, repeat step 2 and retest.
This is why I always start by adding only a little bit of mineral spirits. I can thin the stain further, but I can’t darken the stain if I dilute it too much.
I’m going to make this simple: thinning gel stain is a bad idea. The whole purpose of gel stain is to be thicker than traditional wood stain, so that less stain soaks into the wood and therefore the wood is less blotchy.
Gel stain is a great, versatile stain (and if you’re not using it, you should check out my complete guide here, so I can convince you of its awesome-ness,) but it’s not meant to be thinned.
If you’re tempted to thin gel stain, just purchase traditional wood stain instead.
And if you’re not going to listen to me and are planning to thin it anyway, well, gel stain also thins with mineral spirits, and the exact same process I described above applies to gel stain too.
Water-based stains can be thinned with, you guessed it, water. However, it’s worth noting that oil-based wood stains tend to produce deeper colors than water-based stains, and water-based stains often require multiple coats to produce the same shade as an oil-based stain.
Because of this, you might be making life more difficult for yourself by thinning a water-based stain. A thinned water-based stain might need even more coats to produce the color you want.
The moral of this story: always test your stain before you decide to thin it. You might not need to thin it at all.
Regardless, here’s how to thin water-based stain:
Step 1: Pour Stain
Just like with oil-based stain, it’s best to work in a separate container, so you don’t thin more stain than you actually need.
I usually start with a half of cup of stain, unless I’m working with a larger project.
Step 2: Add Water
Add one tablespoon of water to the stain, mixing thoroughly after adding the water.
Step 3: Test Stain
Test the stain on some scrap wood to see if it is the desired color and consistency. Repeat step 2 if to further dilute the stain.
I’ve got a quick warning story before we move on. I was staining this TV lift cabinet, and was nearing the end of my water-based stain. I’d stained most of the piece, and only had this little bit inside the cabinet left.
I didn’t have enough stain to really finish the whole inside portion, so I added some water to the stain in hopes of making it last longer.
There were clumps of pigment in the can, so I thought it would be fine after a bit of mixing. When I applied the stain, it looked fine, but once it dried it was super chalky:
Moral of this: be very wary of thinning the clumps of pigment at the bottom of the can. Instead, try to make sure those are mixed in with the stain from the get-go.
Lacquer-based stains exist, and I don’t want ignore them. However, they’re pretty difficult to find for the average homeowner, and mostly exist in commercial and production settings.
Lacquer sprays well and dries quickly, so it can be recoated in under an hour, which is the main reason it’s so popular with contractors and other professionals.
These features, however, make it difficult for the average woodworker to use successfully without special equipment (aka, a high-volume low-pressure sprayer, which costs $500+)
If for some reason you’ve come across lacquer-based stain and want to thin it, it can be thinned in a similar manner to oil and water-based stains, except using lacquer thinner instead mineral spirits or water.
Keep in mind that lacquer dries incredibly quickly, so you’ll need to work fast.
How to Apply Thinned Wood Stain
Step 1: Thoroughly Mix the Stain
Hopefully you just thinned the stain and it’s well-mixed, but if that’s not the case, stir it well. Pigments fall to the bottom of the container really quickly.
I’m always surprised how diluted the stain looks if I walk away for a few minutes while I’m staining, and forget to stir when I come back.
Step 2: Apply the Stain
I really like applying stain with a rag, as I feel it helps me control how much stain is absorbed into the wood. However, a foam brush works too if that’s what you prefer.
Step 3: Wipe Off Stain
If you apply with a foam brush, any excess stain will need to be wiped off after 3-5 minutes. If you applied with a rag in the first place, this isn’t an issue.
Step 4: Wait for the Stain To Dry
The dry time for stain depends on the type of stain you used – water based stain dries significantly faster than oil-based stain. Follow the directions on the original stain for dry and recoat times.
If you’ve used a water-based stain, sand the wood before the next coat. Water-based stains raise the grain of the wood, and therefore require sanding after the first coat. They do not require sanding after additional coats.
Oil-based stains do not need to be sanded in-between coats.
Step 5: Recoat
Repeat steps 1-4 as many times as necessary to achieve your desired color. Then finish the piece. If you’re not sure which finish to use, check out my post on choosing a wood finish.
A Few Wood Stain Safety Notes
If you’re working with water-based stain, there aren’t that many safety rules to remember. Water-based stain is less toxic that oil-based, and isn’t made from flammable ingredients.
However, oil-based stains, mineral spirits and gel stain can all be dangerous. First off, they emit toxic fumes that are hazardous to breath. If you’re going to be thinning stain, work outside or in a well-ventilated area.
Secondly, these stains are flammable. Stay away from heat and ignition sources while working.
Thirdly, any rags used during the staining process need to be disposed of carefully. Lay the rags out to dry, making sure they’re not folded or bunched in any way. Rags saturated with oil-based stain can spontaneously combust (I’m not joking,) so it’s very important that they can dry quickly.
Once the rags are dry, they’re no longer dangerous, and can be disposed of normally.
Finally, if for some reason you have extra stain that you need to get rid of, don’t just toss it in the trash. Liquid wood stain is classified as a hazardous material, and therefore needs to be disposed of carefully.
Luckily, if you have some scrap wood or cardboard, you can avoid a trip to the hazardous materials center. Paint the stain onto the wood or cardboard, and let it dry completely. At that point, the stain is no longer hazardous, and the cardboard/wood can be thrown away.
Diluting Wood Stain: Tips for Success
Tip #1: Always Test Your Stain
This is especially important when diluting the wood stain, but is something you should do before you ever apply stain to the piece. Always grab a piece of scrap wood from the build, and test your stain to see how it looks.
I typically test a couple of different options: applied with a brush, applied with a rag, wood conditioner, no wood conditioner, etc. The more options I have to choose from, the better my piece will look in the end.
And not only should you test the stain, you should test the finish as well! Wood finish can dramatically alter the look of your piece. So after you’ve decided on a staining method, test a few wood finishes as well.
Does the stain still look the way you want it to? If not, you might want to adjust the amount you thin the stain!
Pro Tip: If you’re working on a piece you didn’t build, and don’t have any scrap wood from, you should still test the stain! Simply test on an inconspicuous part of the wood (like the underside of a tabletop) instead of somewhere visible.
Tip #2: Add Thinner Slowly
I put this in the instructions, but it never hurts to say it again. It’s much easier to thin stain than it is to thicken it. Add thinner slowly, and test the stain frequently.
You’re much more likely to have a successful end result if you’re regularly testing the stain to ensure you get the exact color and consistency you’re looking for.
Tip #3: Don’t Thin Too Much
It is possible to thin your stain too much! In that case, the stain is drippy and hard to apply. Luckily, this isn’t quite as big of a deal as it is with finish, since wood stain is wiped off the piece, and the drip won’t dry into an ugly blob.
Regardless, drips can result in uneven staining, so it’s best to avoid them. Be watching for drips as you test your diluted stain, and you should be fine.